1. Field of the Invention
The present invention relates to a freeze indicator, and more particularly, to a freeze indicator capable of easily confirming whether products are exposed to a freezing temperature or less using a development medium member containing a development material having hydrophobic property and moisture, and using diffusion characteristics of the development material into a development medium only when the moisture is frozen at a freezing temperature or less of the moisture.
2. Discussion of Related Art
As a refrigeration and freezing industry is advanced, foods and medicines that require freezing and refrigeration should be appropriately managed, and in particular, milk products, fishes and fruits that require a strict temperature management during distribution should be always maintained in a fresh state during the entire distribution process from producers to consumers. In addition, the medicines also should be maintained and managed at an appropriate storage temperature.
However, a consumer in a final consumption step can only visually determine whether the foods is in an appropriate refrigeration and freezing state in a purchase step but cannot determine whether the foods have been stored at an appropriate temperature throughout the entire distribution process. Further, a professional manager who manages distribution of refrigerated and frozen foods also cannot easily check whether the foods are distributed in a safe refrigeration and freezing state in many cases.
Accordingly, while a plurality of methods and apparatuses for checking a freezing and refrigeration state of the foods during the distribution have been disclosed, the conventional methods and apparatuses cannot precisely determine whether the products are maintained in the safe refrigeration and freezing state throughout the entire distribution process.
In order to solve the problems, various kinds of precise temperature and time indicator (TTI) (an instrument or a label attached to each of the products and configured to display temperature and time records accumulated in the product) have been developed and used.
However, the above-mentioned temperature and time indicators are mostly operated when the product is exposed to an environment of a specific temperature range or more, and there are only a few temperature and time indicators capable of confirming whether the products are exposed to the frozen state and a certain time elapses from the frozen state.
U.S. Pat. No. 8,122,844, entitled “Freeze Indicators with a Controlled Temperature Response,” discloses a conventional freeze indicator.
FIG. 1 is a view schematically showing a conventional freeze indicator 1. The conventional freeze indicator 1 includes a lower substrate 2, a lower plate 6 stacked on the lower substrate 2, an upper plate 8 attached to the lower plate 6 with an adhesive agent 3, a freezing particle element 5 filled in a space disposed between the lower plate 6 and the upper plate 8, and an air bubble 7 disposed on the upper plate 8.
In the freeze indicator 1, since the air bubble 7 freely moves at a freezing temperature or more of the freezing particle element 5, it will be appreciated that the freeze indicator 1 is distributed at a freezing temperature or more, and since the freezing particle element 5 is frozen and held in a solid state at the freezing temperature or less, it will be appreciated that the product is distributed at the freezing temperature or less because the air bubble 7 is fixed to one position without moving.
However, the conventional freeze indicator 1 can only inform a user of whether products or goods to which the indicators are attached are maintained in a state of the current freezing temperature or lass, but cannot appropriately confirm whether (i) the product is exposed to the frozen state in the past and (ii) a certain time elapses from the frozen state.
Moreover, an already used conventional freeze indicator has disadvantages of (iii) a complex configuration, or (iv) precision is decreased upon an actual operation.
Accordingly, in order solve the problems of the conventional freeze indicator and further improve functions thereof, the inventor(s) has invented a freeze indicator capable of easily confirming whether products are exposed to a certain temperature or less using a development medium member containing a development material having hydrophobic property and moisture, and using diffusion characteristics of the development material into a development medium only when the moisture is frozen at a freezing temperature or less of the moisture.